1. Field of the Invention
The present invention relates to an engine having a crank case of a variable volume that varies volume of the crank case according to movements of a piston.
2. Description of Related Art
Illustrated as one example, a blow by gas that escapes through a fine gap between a piston and a cylinder is formed during a combustion of an engine, if it is exhausted to the outside, the atmosphere pollution is caused thereby, and if the blow by gas is inappropriately handled, an interior pressure of the crank case is increased and the engine can be exploded thereby.
The blow by gas that is formed during the combustion of the engine is transferred to a head cover through a blow by passage that is formed by penetrating a cylinder block and a cylinder head from the crank case. The blow by gas that flows into the head cover passes a baffle plate to filter oil of the blow by gas is again supplied to an intake system through a PCV valve (Positive Crank case Ventilation Valve) and a breather, and then it is supplied into the combustion chamber again.
If the blow by gas is not circulated to the intake system to be combusted, the pressure increment of the crank case can cause the engine to be fail. The blow by gas is to be recirculated through a blow by passage of the cylinder block and the cylinder head between the crank case and the head cover so as to secure smooth flowing of the blow by gas. For this purpose, it is necessary to enlarge the crank case or widen a cross-section of the blow by gas passage.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.